EyeWorld Asia-Pacific June 2024 Issue

The Asia-Pacific Association of Cataract and Refractive Surgeons

Vol. 20 No. 2 June 2024

THINGS TO THINK ABOUT

PLUS The Long & Short of it All: Experienced perspectives on perioperative complications

In Depth and Within Sight: A broad look at perioperative issues dominating surgical procedures

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EyeWorld Asia Pacific | June 2024

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EyeWorld Asia Pacific | June 2024

CONTENT

CORNEA 27

EDITORIAL 4 Things To Think About

Peripheral Ulcerative Keratitis Diagnosis And Management 29 Treatment Of Limbal Stem Cell Deficiency 33 Physician Perspective: Why Are Cornea Specialists Failing Patients With Limbal Stem Cell Deficiency?

REFRACTIVE SURGERY 16 Current Accommodating Lenses In Development 20 Taking A Closer Look At ICL Sizing And Vault Concerns 24 Clearing Up The Confusion:

CATARACT 6 Handling Persistent Foreign Body Sensation 10 Cataract Surgery In Short Eyes 12 A New Understanding For Ocular Dominance

GLAUCOMA 35

Get The Right Anterior Chamber Depth For ICL

The Effect Of Intravitreal Injections On Glaucoma Procedures 39 Current Perspectives On NTG And Progression At Low IOPs

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be considered as a method to address diplopia following cataract surgery. We are accustomed to thinking that the dominant eye should always be corrected for distance but in reality clinical experience suggests that this is not always the case. Published studies have documented that there is no difference in patient satisfaction among patients who have undergone cataract surgery, while presenting with a modest level of monovision to correct a distanced eye. Although deciding what level of myopia to target, along with eye dominance may seem daunting to a surgeon unaccustomed to using modest monovision in cataract surgery, the reality is that many of these issues can be avoided by targeting a modest level of myopia of -1.25 dioptres. I consider this to be the “magic” number because any negative impact of monovision on stereo acuity is relatively minor at -1.50 dioptres of anisometropia or less and a reduction in bilateral contrast sensitivity is only encountered at higher levels of anisometropia. Furthermore, the issue of dominance at this level of anisometropia is less relevant. As mentioned, patient satisfaction has not suffered, whether the dominant eye is targeted for distance or near at this level of myopia. Having utilized modest monovision for many years in approximately 75% of all cases undergoing cataract surgery, I can summarize the secret of success through four points: the A , B , C , D of Monovision.

Graham Barrett Chief Medical Editor EyeWorld Asia-Pacific • China • Korea • India

Things to Think About The current issue of EyeWorld Asia Pacific provides lots to think about, when it comes to covering current and frequently encountered issues that arise during cataract surgery. These encompass every topic, from the relatively mundane issues like post-surgical management of foreign body sensation, to futuristic prospects like how intraocular lenses can be more widely used. One of the most interesting topics is the discussion about what we presently understand of ocular dominance — particularly in relation to utilizing modest monovision in Cataract and Refractive surgery. The decision of whether to perform monovision is more complex, however, when the clarity of vision is impacted by significant cataract. Testing for dominance is less reliable and contact lens trials are of little use when the vision is impaired. Monovision can be considered as Mini Monovision in the range of up to -0.50 diopter, Modest Monovision with a range from -0.75 to -1.50 diopters, and Classical Monovision when the myopic target in one eye is -1.75 diopters and greater. An additional category of Extreme Monovision in the range of -3.00 dioptres and greater can

Address the alternatives, which include monofocal IOLs, multifocal IOLs and accommodative IOLs.

Broach the option of monovision, emphasizing the maintenance of optimum quality of vision and reversibility. Emphasize that modest monovision provides excellent intermediate vision but not total spectacle independence.

Choose the eye with the denser cataract and poorest vision as the first eye for surgery targeting emmetropia.

Demonstrate the impact of -1.25 diopters by adding a +1.25 D lens in a trial frame on the recently operated eye to demonstrate the impact of the defocus on distance vision and the level of reading expected if this target is achieved. Generally, a minimum level of unaided vision of 6/9 is required in the first eye that has undergone cataract surgery for a patient to be a good candidate for modest

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monovision. Patients should always be able to comprehend the discussion and reason for selecting this modality.

EDITORIAL BOARD Chief Medical Editor Graham Barrett, MD

Occasionally, one can deviate from these guidelines. A patient who has always been significantly more myopic in one eye is likely to be more satisfied if the relationship between the two eyes is maintained. If the more myopic eye has a more dense cataract, I would still prefer to do this eye first but rather target this for near distance, unlike my usual routine. Similarly in patients with pre-existing high myopia, a target of -1.50 diopters instead of -1.25 diopters is recommended as these patients expect better unaided reading vision. Using these guidelines, the strategy of modest monovision has proved to be remarkably successful in providing a presbyopic solution to patients with a high level of satisfaction. Although modest monovision as this can be reversed using laser correction, this is exceptionally rare using these guidelines. When one targets a modest level of myopia, not all formulae will maintain accuracy. We have published a paper previously showing that the prediction accuracy for the Universal II formula is not impacted significantly by targeting a myopic outcome rather than emmetropia. Depending on the optical principle of a particular lens model, using extended depth of focus IOLs are well suited to being used in combination with modest monovision. An appropriate Extended Focus or Monofocal+ IOL provides better reading for a low level of myopia and the impact on stereo acuity is minimized due to the overlap of the defocus curve for the distance and near eyes. Similarly, the impact on distance acuity is less in the presence of residual myopia. Advanced methods of testing dominance are certainly worth evaluating, but using modest monovision within my clinical practice over many years have shown the practical effectiveness and reliability of these guidelines. these practical guidelines have proved to be extremely effective in using modest monovision in my clinical practice over many years. I hope this discussion provides you with “something to think about”, as you consider the different ideas curated within this issue of EyeWorld Asia Pacific.

CHINESE EDITION Regional Managing Editor Yao Ke, MD Deputy Regional Editor He Shouzhi, MD

INDIAN EDITION Regional Managing Editor Abhay Vasavada, MD Deputy Regional Editor S. Natarajan, MD KOREAN EDITION Regional Managing Editor Hungwon Tchah, MD Deputy Regional Editor Chul Young Choi, MD Hiroko Bissen-Miyajima, MD Japan Kimiya Shimizu, MD Japan Sri Ganesh, MD India Chee Soon Phaik, MD Singapore Johan Hutauruk, MD Indonesia

Zhao Jialiang, MD Assistant Editors Zhouqi, MD Shentu Xingchao, MD

EDITORIAL MEMBERS Chan Wing Kwong, MD Singapore Ronald Yeoh, MD Singapore John Chang, MD Hong Kong SAR Pannet Pangputhipong, MD Thailand YC Lee, MD Malaysia PUBLISHING TEAM Chief Publisher Ronald Yeoh, MD Executive Director Kathy Chen kathy.chen@apacrs.org

Publishing Consultant Donald R Long don@apacrs.org Production Team Gretel Tan Aileen Bian ewap@apacrs.org

APACRS Publisher: EyeWorld Asia-Pacific Edition (ISSN 1793-1835) is published quarterly by the Asia-Pacific Association of Cataract & Refractive Surgeons (APACRS), c/o Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751, telephone (65) 6322-7469, fax (65) 6327-8630, email ewap@apacrs.org. Printed in Singapore. Editorial Offices: EyeWorld Asia-Pacific Edition: Asia-Pacific Association of Cataract & Refractive Surgeons (APACRS), c/o Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751, telephone (65) 6322-7469, fax (65) 6327-8630, email ewap@apacrs.org. Advertising Office: EyeWorld Asia-Pacifi c Edition: Asia-Pacific Association of Cataract & Refractive Surgeons (APACRS), c/o Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751, telephone (1-703) 975-7766, email don@apacrs.org. Copyright 2021, Asia-Pacifi c Association of Cataract & Refractive Surgeons (APACRS), c/o Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751, telephone (65) 6322-7469, fax (65) 6327-8630, email ewap@apacrs.org. Licensed through the American Society of Cataract & Refractive Surgery (ASCRS), 4000 Legato Road, Suite 700, Fairfax, VA 22033-4003, USA. All rights reserved. No part of this publication may be reproduced without written permission from the publisher. Letters to the editor and other unsolicited material are assumed intended for publication and are subject to editorial review and acceptance. The ideas and opinions expressed in EyeWorld Asia-Pacific do not necessarily reflect those of the editors, publishers or its advertisers. Subscriptions: Requests should be addressed to the APACRS publisher, c/o Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751, telephone (65) 6322-7469, fax (65) 6327-8630, email ewap@apacrs.org. Back copies: Subject to availability. Contact the APACRS publisher, c/o Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751, telephone (65) 6322-7469, fax (65) 6327-8630, email ewap@apacrs.org. Requests to reprint, use or republish: Requests to reprint or use material published herein should be made in writing only to the APACRS publisher, c/o Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751, telephone (65) 6322-7469, fax (65) 6327-8630, email ewap@apacrs.org. Change of address: Notice should be sent to the APACRS publisher, c/o Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751, six weeks in advance of effective date. Include old and new addresses and label from a recent issue. The APACRS publisher cannot accept responsibility for undelivered copies. KDN number: PPS1766/07/2013(022955) MCI (P) 038/02/2024

Warmest regards Graham Barrett

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Handling Persistent Foreign Body Sensation by Ellen Stodola, Editorial Co-Director

Foreign body sensation (FBS) is a common issue that may be associated with a wide range of conditions, which could present with different signs and symptoms. Two physicians discussed this problem, including when they’re most likely to present and how they can be diagnosed.

“It’s difficult to guess at percentages, but I think all patients are likely to experience some form of irritation in their life including FBS. In my experience, a specific patient subgroup of roughly 10% do experience severe forms of FBS that are recalcitrant to treatment,” said D. Brian Kim, MD. The persistence of FBS implies chronicity, he said, which may include dry eye syndrome, blepharitis, or allergic conjunctivitis. Anatomical comorbidities involving the eyelid such as floppy eyelid syndrome, conjunctivochalasis, epithelial basement membrane dystrophy, and recurrent corneal erosions can exacerbate the problem as well. Rony Sayegh, MD, said that persistent FBS is when an individual experiences the sensation that there is something gritty, scratchy, or uncomfortable in their eye, even when no actual foreign object is present. The prevalence of persistent FBS can vary depending on the underlying causes and the population being studied, he said, adding that it’s a relatively common complaint that ophthalmologists encounter. He also noted dry eye as one of the most common causes, affecting a significant portion of the population. How much does cataract surgery contribute to FBS? Dr. Sayegh said that FBS of varying severity, persisting for 3 or more months after cataract surgery, seems to occur in about 10–15% of patients. Although the mechanism is not fully understood, there are a number of possible reasons for this postoperative FBS, he said.

Local edema over the incision from surgical trauma is one possible factor, and microcystic edema, or even frank bullae, can be seen on exam. Hypertonic saline solution can be helpful in these cases as the edema is often transient. Persistent inflammation is another cause that is not well understood. Patients with a history of dry eye, diabetes, underlying connective tissue disease, or certain nutritional alterations may be at a higher risk. Damage to corneal nerves at the incision site is another potential cause. Severing corneal nerves can lead to alterations in the functional tear unit with decreased tear production, reflex tearing, and decreased release of

Local edema over the incision from surgical trauma is a possible reason for FBS after cataract surgery, and microcystic edema, or even frank bullae, can be seen on exam. Source: Rony Sayegh, MD This photo shows the thin profile of the Kim Corneal Sweeper and the well-demarcated fold in the epithelium highlighted by fluorescein dye and cobalt blue light. Source: D. Brian Kim, MD

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neuroprotective agents, all resulting in dry eye and damage to the ocular surface that can be perceived as FBS. Furthermore, aberrant regeneration of the severed nerves and possibly neuroma formation can result in persistent FBS. Dr. Kim also discussed how cataract surgery can exacerbate the problem. “First, a whole host of medicated eye drops are given preoperatively, intraoperatively, and postoperatively, and these drops contain preservatives, which are toxic to the ocular surface. Betadine can also irritate the eye,” he said. “Second, the very act of surgery severs corneal nerves, which can reduce corneal sensation. Moreover, cutting the cornea can damage the epithelial basement membrane adhesions and result in a recurrent corneal erosion.” He added that typically, recurrent corneal erosion is associated with accidental injury, but it’s important not to forget that surgery is also a form of trauma to the cornea, particularly clear corneal phaco. “The most important precaution is to identify comorbid conditions and counsel patients during the preoperative discussion, so they are made aware and begin treatment before surgery.” Presentation and common complaints In some cases, patients will explicitly say, “I never had FBS until after you did my cataract surgery,” Dr. Kim said. This is a challenge because even if you improve the patient’s visual acuity, they may dwell on the FBS, which they will reiterate only began after you performed surgery. Some of this can be subclinical dry eye or blepharitis manifested from surgery, while others can have an underlying epithelial basement membrane dystrophy or corneal erosion.

that seem to worsen or alleviate the discomfort, underlying health issues, and environmental exposures can be very helpful,” Dr. Sayegh said. “In addition, resolution of the FBS with instillation of a drop of anesthetic in the office is often helpful in narrowing the differential diagnosis. Slit lamp examination, which includes eyelid eversion as well as use of vital dyes, can help make the diagnosis in the great majority of patients.” Dr. Sayegh said that more specific diagnostics such as tear osmolarity, MMP-9, meibomian gland imaging, and confocal microscopy can also be helpful. When diagnosing FBS, Dr. Kim said it’s important to first treat the common conditions, namely dry eye and blepharitis. However, even after aggressive treatment, patients may not improve, and the patient and physician can be left perplexed and frustrated, he said. “It’s important to consider that these cases could actually be a form of recurrent corneal erosion not visible on slit lamp examination.” Typically, Dr. Kim said that recurrent corneal erosions are diagnosed by identifying irregular or negative staining with fluorescein dye or looking for irregularities on corneal topography. However, he noted that identification relies on a high index of suspicion since there is no good definitive diagnostic tool. A dried Weck-Cel sponge has been used to touch the corneal surface to identify areas of loose epithelium, but the dry sponge can stick to the cornea and induce an abrasion. “As a result, I developed the Kim Corneal Sweeper [Corza Medical], which is a handheld instrument with a straight handle and fusiform shape tip with rounded edges,” he said. “The smooth texture enables safe use on the corneal surface. Fluorescein dye is instilled, and the cornea is examined under the slit lamp with cobalt blue light. The sweeper is held like a pencil and pressed

“A good history including a good description of symptoms, when they began, how they’ve progressed, and any factors

Foreign objects, such as contact lenses or even bugs, can get stuck in the eye or under the eyelid, causing FBS. Source: Rony Sayegh, MD

Certain systemic drugs can also cause corneal changes and FBS. The slit lamp photograph shows microcyst-like epithelial changes in a patient on Mirvetuximab soravtansine, an antibody drug conjugate used for the treatment of ovarian cancer. Source: Rony Sayegh, MD

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tangentially against the cornea with steady indentation pressure along the entire corneal surface. The tear film enables it to glide over the cornea atraumatically.” Elaborating further on the use of the sweeper, Dr. Kim explains, “When an area of loose epithelium is encountered, it ripples up, which creates a visible fold easily seen due to the thin profile and enhanced by the fluorescein dye. Typically, the area of loose epithelium is isolated and well-demarcated. We published a study using the corneal sweeper to detect these hard-to-find corneal erosions and discovered that more than 80% of these patients experienced some improvement or resolution of symptoms after treatment. 1 ” Management process The treatment for FBS depends on the underlying cause. Since foreign body sensation can be due to various factors, Dr. Sayegh suggested some general approaches and treatments: 1. Identify and treat the underlying condition. Remove any foreign bodies and exposed concretions, optimize the ocular surface. Treat conditions appropriately with antibiotics, antihistamines, and/or steroids. Hypertonic saline can help with corneal edema and epithelial basement membrane dystrophy. Use lid hygiene for meibomian gland dysfunction and blepharitis. Response to therapy can sometimes help determine the main underlying cause of the FBS, and optimizing that line of treatment, whether it is using plugs in patients who find artificial tears helpful or cyclosporine in patients who find steroids helpful, can increase the odds of success. 2. Place a drop of Proparacaine in the eye. Asking if that helps relieve the FBS can help diagnose corneal nerve dysfunction. Warm compresses not only help with blepharitis and meibomian gland dysfunction but seem to help reduce nerve pain as well. Autologous serum tears remain the most effective treatment for the neuropathic form of FBS and have been shown to help regenerate corneal nerves on confocal microscopy. Scleral lenses can also be helpful in some cases. 3. Avoid rubbing. Rubbing the eyes can exacerbate irritation and FBS. Dr. Sayegh has used wristbands that vibrate when patients attempt to touch their eyes (designed for trichotillomania) with some success.

Persistent foreign body sensation in the eye can be caused by a variety of conditions and factors, Dr. Sayegh said. Some of the most common ones include: Dry eye syndrome: Dry eye is a broad term that includes any condition in which tears are impacted, in quantity, quality, composition, or distribution on the ocular surface. Blepharitis, meibomian gland dysfunction, and conjunctivochalasis are very common conditions that are part of the dry eye syndrome, and a gritty or sandy feeling in the eyes is commonly reported by patients with these conditions. Conjunctivitis: This includes allergies, which are very common, as well as viral conjunctivitis. Patients often report itching, irritation, redness, and the sensation of a foreign body in the eye. Everting the eyelids can be helpful in the diagnosis of these conditions to look for follicles and papillae, Dr. Sayegh said. Contact lens issues: FBS can be a symptom of a poor fit or contact lens spoilage or related to a complication of contact lens wear, such as a corneal abrasion or ulcer. It is also important to ask if wearing the contact lens helps with the FBS, which can occur in some patients, such as those with limbal stem cell deficiency. Foreign body: Sometimes a small foreign object can actually get stuck in the eye or under the eyelid, leading to FBS. “We have seen contact lenses retained for decades. One should not forget conjunctival concretions are common and can sometimes break through the surface and cause FBS,” he said. Environmental factors: Wind, smoke, dust, and other environmental factors can cause foreign body sensation. “Some of my patients who work long hours outdoors or at the grill have benefited from protective goggles,” he said. Eye strain: Prolonged periods of reading or using digital screens can cause eye strain, leading to discomfort which may include FBS. Corneal erosions: These are also a common cause of FBS and include epithelial basement membrane dystrophy and recurrent erosion syndrome. It is important to look carefully for patterns of negative staining that are indicative of these conditions, he said. Other dystrophies are often easier to diagnose based on corneal appearance. Certain systemic drugs such as novel cancer treatments can also cause corneal changes and FBS.

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ASIA-PACIFIC PERSPECTIVES

Jacqueline Beltz, MD 2/232 Victoria Parade, East Melbourne, Vic 3002 Australia jacquelinebeltz@mac.com

Both Dr. Sayegh and Dr. Kim describe cataract surgery as a common contributor to FBS, providing valuable perspectives on the challenges encountered by patients and ophthalmologists during the postoperative period. By delving into potential mechanisms such as local oedema, inflammation, and nerve damage, Dr. Sayegh illuminates the interplay between surgical trauma and the integrity of the ocular surface. His analysis astutely underscores the importance of recognising predisposing factors and implementing targeted interventions to effectively manage postoperative FBS, thereby improving patient satisfaction and ocular comfort. I also agree with Dr. Kim who points out that Betadine and topical medications likely also play a role. While the exploration of FBS aetiology is intellectually stimulating, we should acknowledge that patients primarily seek relief from their symptoms. Despite the complexity of underlying causes, the armamentarium of treatment options remains relatively unchanged. Unpreserved lubricants, topical steroids, and/or cyclosporine, coupled with patience, constitute the cornerstone of management. It is crucial for Ophthalmologists to convey to their cataract surgery patients that FBS is a common and expected phenomenon postoperatively. I often liken it to the healing process of a cut or graze on the skin, explaining that as the

eye undergoes repair, sensations of dryness or itchiness will arise but can be alleviated with time and supportive treatments. Setting realistic patient expectations is paramount in managing postoperative FBS. By providing reassurance and explaining the transient nature of these symptoms, we can mitigate patient anxiety and improve adherence to treatment regimens. While persistent FBS beyond three months poses a clinical challenge, I do not find the incidence to be as high as 10-15% as described by Dr. Sayegh. Timely recognition of refractory cases is important as it allows for further investigation, management, and most importantly, patient support. By integrating clinical expertise with patient-centred care, Ophthalmologists can navigate the complexities of FBS aetiology while prioritising symptom relief and enhancing patient well-being. As we continue to refine our understanding and therapeutic approaches, collaboration and dialogue within the ophthalmic community will undoubtedly drive advancements in postoperative care and improve patient outcomes.

Editors’ note: Dr. Jacqueline Beltz is a consultant for Alcon, Johnson and Johnson, and Acufocus.

About the Physicians D. Brian Kim, MD | Professional Eye Associates, Dalton, Georgia | docdbk100@gmail.com Rony Sayegh, MD | Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio | rrs109@case.edu

Relevant Disclosures Kim: None Sayegh: None

Reference 1. Kim ME, Kim DB. Implementation of the corneal sweep test in the diagnosis of recurrent corneal erosion: a 2-year retrospective study. Cornea . 2022;41:1248–1254.

This article originally appeared in the March 2024 issue of EyeWorld. It has been slightly modified and appears here with permission from the ASCRS Ophthalmic Services Corp.

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Cataract Surgery in Short Eyes

by Ellen Stodola, Editorial Co-Director

Short eyes are often the most challenging condition for cataract surgeons to manage. Preoperatively, lens selection can be tricky, as the effective lens position is hard to predict in these eyes. These patients are often hyperopic to begin with, and may be less accepting of a myopic result. Intraoperatively, issues with effusions and iris prolapse can make a routine case very complicated. Even after surgery, patients may need to be monitored for chronic angle closure from peripheral anterior synechiae or may need to be treated for aqueous misdirection should it occur. JoAnn Giaconi, MD, and Sahar Bedrood, MD, PhD, are both glaucoma specialists and cataract surgeons who have dealt with their fair share of short eyes. In this month’s YES Connect column, they review their approach to short eyes. They discuss their methods for lens selection and provide pearls of wisdom on how to avoid complications like iris prolapse and effusions. A prominent pearl to highlight: Do not underestimate how helpful relieving some posterior pressure at the start of cataract surgery can be. Placing a pars plana trocar and removing some vitreous will immediately deepen the anterior chamber, and the rest of the surgery will go routinely.

– Mitra Nejad, MD, YES Connect Editor

Performing cataract surgery in short eyes comes with certain challenges and considerations. Two surgeons discussed how to approach these patients, as well as certain formulas and surgical approaches that can help in these cases. Sahar Bedrood, MD, PhD, and JoAnn Giaconi, MD, defined a short eye as one that is less than 22 mm in axial length. “Less than 21 mm is where I personally will start making some adjustments to technique. For others it is less than 20 mm,” Dr. Giaconi said.

Dr. Bedrood said that patients with an axial length of less than 22 mm typically are hyperopic and may have narrow angles. “I perform intraocular pressure checks and gonioscopy to rule out angle closure, which would require IOP-lowering drops or more imminent cataract surgery for lens removal,” she said. “Accurate axial length measurements are key because we know that small deviations from the correct axial length in short eyes can lead to large refractive error.

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Therefore, I do measurements with both partial coherence interferometry (IOLMaster, Carl Zeiss Meditec) and optical low coherence reflectometry (Lenstar, Haag-Streit). This allows me to cross check the measurements for accuracy. I would also consider doing a UBM to measure scleral thickness, as we know that is a risk factor for choroidal effusions and possible malignant glaucoma following surgery.” If the axial length is <18 mm or the sclera appears thickened and Dr. Bedrood notices a uveal effusion (high IOP and shallowing of chamber at the time of surgery), she said she anticipates the possibility of scleral windows. Dr. Bedrood said that a short eye might leave patients at a slightly higher risk for postoperative complications like iris prolapse, corneal edema, malignant glaucoma, and CME. Dr. Giaconi said that she will let patients know that a short eye tends to have crowded anatomy and that it is at higher risk for certain complications, like iris prolapse, which can lead to transillumination defects postoperatively. It can also be more difficult to remove the lens, and therefore, there is a higher risk for corneal edema. “Predicting where the lens implant will end up in the eye is also more difficult, so hitting the refractive target is less certain,” she said. Dr. Bedrood agreed that lens calculations may be different with these short eyes. “I make the patient aware that the lens calculations are made based on formulas that consider the dimensions of the eye,” Dr. Bedrood said. “Since the dimensions of their eyes fall in an ‘abnormal’ range, then we have some limitations with the formulas and a possibility of postoperative refractive error is possible. Over the last few years, however, we have had newer lens formulas developed to help reduce the chance of refractive error.” Dr. Giaconi recommends newer IOL calculation formulas. “There are some studies showing the Kane formula as promising for short axial lengths,” she said. “I like the new [ESCRS] IOL calculator which shows multiple formulas of the newest generation and allows me to compare multiple formulas.”

Dr. Bedrood said that, in the past, the formulas that were suggested for use in short axial length eyes were the Haigis and Hoffer Q formulas. “There are newer formulas that we now implement into our practice,” she said, adding that the K6 formula and the Kane formula are multivariate formulas that have shown good success for obtaining targeted refractive outcomes in the shorter eyes. 1 Short eyes are more difficult to operate in, Dr. Giaconi said. There can be more positive posterior pressure; the anterior chamber is often shallow; the capsulorhexis can have a tendency to run out; and iris prolapse is more common, which can lead to iris damage. “For shorter eyes, I will administer IV Mannitol about an hour before surgery (20 grams), if the patient can tolerate it. This dehydrates the vitreous and removes positive posterior pressure,” Dr. Giaconi said. “If Mannitol isn’t safe, some people will use Acetazolamide preoperatively,” she continued. “If the AC is very shallow, a limited pars plana vitrectomy can be done. “If one isn’t comfortable doing this themselves, one can partner up with a retina surgeon to do it, especially if a retina surgeon operates on the same day as you in your operating rooms,” she said. “It takes them just a couple of minutes to complete and can significantly deepen the anterior chamber and make operating much easier.” Dr. Bedrood said the initial surgical challenge with these eyes is the posterior pressure and the small space within the anterior chamber, which makes it challenging to maneuver instruments. She also recommended using IV Mannitol preoperatively to help decompress the vitreous and move the lens more posteriorly. “I also recommend a femtosecond laser for the rhexis so that there is less potential for the cornea to be touched by instruments during the creation of the rhexis,” she said. “Other considerations include the possibility of iris prolapse, so I will have iris hooks on standby.”

About the Physicians Sahar Bedrood, MD, PhD | Glaucoma & Cataract Surgeon, Advanced Vision Care, Los Angeles, California | saharbedrood@gmail.com JoAnn Giaconi, MD | Stein Eye Institute, University of California, Los Angeles, California | giaconi@jsei.ucla.edu

Reference 1. Sandhu U, et al. Comparison of IOL calculation formulas for long and short axial length eyes. Invest. Ophthalmol Vis Sci . 2023;64(8):1203.

Relevant Disclosures Bedrood: Abbvie, Glaukos, Thea Laboratories, Ocular Therapeutix, BVI, Elios Vision Giaconi: LightTouch

This article originally appeared in the March 2024 issue of EyeWorld. It has been slightly modified and appears here with permission from the ASCRS Ophthalmic Services Corp.

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by Liz Hillman, Editorial Co-Director A New Understanding for Ocular Dominance

One might think that the topic of ocular dominance is simple, set, and well understood. But in actuality, there are some recent findings that might have an impact on the concept and its relevance to lens selection and target setting for monovision and blended vision.

“There’s more to it than we think,” said Arthur Cummings, MD.

A group of ophthalmologists in the U.S. decided to use the SimVis Gekko to test for sensory dominance more definitively in their patient populations, assessing what the brain really prefers as far as dominance. This study included 269 patients enrolled at five centers. “The way that it’s done is by putting a 1.5 lens in front of the eye electronically and asking the patient if they prefer one or two. The SimVis Gekko does it 10 times really quickly,” Dr. Durrie said. SimVis Gekko The SimVis Gekko (2EyesVision) is, according to the company, a “visual simulator for testing presbyopic corrections.” The device is worn by the patient, and it allows them to “experience the real world through binocular presbyopic premium corrections before intraocular lens implantation, contact lens fitting, or presbyopic laser refractive surgery.”

“The message is: we’re learning more about dominance, and there is some data now to prove that there is more to learn,” said Daniel Durrie, MD. However, he added, further research is needed to understand the implications of this new data. ‘New breakthrough data’ There are two new facts when it comes to the topic of ocular dominance, which physicians like Dr. Durrie and Dr. Cummings are beginning to call sensory dominance. 2. An individual might have a different preference for dominance when you test them for distance vs. near vision. Dr. Durrie started studying ocular dominance with the SimVis Gekko (2EyesVision). Prior to using this device, which not only assigns an ocular dominance preference score but allows the wearer to experience different intraocular lenses and blended vision, Dr. Durrie said ocular dominance was often tested with a hole in a card or with a finger triangle test. 1. There is variance in the level of dominance among patient populations.

Dr. Durrie said he wore the SimVis Gekko himself before choosing his own IOL.

“It was helpful for me in picking my own optics for the IOL. … You could look through it at near and distance, walk around. … Not a lot of [practices] are going to buy this device just to do a dominance test that we don’t know

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SimVis Gekko is a visual simulator that allows the patient to see the real world through any presbyopic correction prior to IOL implantation. Source: 2EyesVision

what usefulness it has, but it comes along with the machine because it’s built into it. If someone wanted to simulate the usefulness of IOLs, which is the purpose of the device, they could do this dominance test also.” The group found the majority of people (more than 50%) are strongly dominant (90– 100% preference for one eye), about a quarter have weaker dominance (70–80% preference for one eye), and a quarter have equidominance (50–60% preference for one eye). “This is new breakthrough data that we have no idea what to do with yet,” Dr. Durrie said, noting that the group that gathered the data would soon be discussing its possible implications, which could lead to future studies. Dr. Durrie said that because the SimVis Gekko is easy to use and integrates well into clinic flow—and because of its usefulness to simulate different types of IOLs and vision options—a practice could start gathering real-world data on patients’ sensory dominance and their distance and near preferences. “Record the data on a group of patients, then keep doing what you’re doing with your IOL selection. Retrospectively come back and if you have patients who were having trouble adapting to their lenses, you can say, ‘Let’s look back and see what preference group they were in,’” he said.

IOL selection and target setting for mono/blended vision Dr. Durrie said that while there is now an expanded understanding of ocular dominance/ sensory preference, it’s too soon to make any practice changes. “Keep doing what you’re doing and let the research develop,” Dr. Durrie said. “This is new information, and I don’t want it to complicate IOL discussions with patients until more data is gathered.” Dr. Cummings said eye dominance remains critically important for lens and target selection. He said it makes “the difference between success and failure.” Like the findings Dr. Durrie spoke about, Dr. Cummings, and Andrew Kopstein, MD, both said they consider not motor dominance but sensory dominance when helping patients choose a lens and setting their target. “Most think that this is motor dominance, where the finger point or thumb forefinger aperture is determinant. It is not. It relies on ‘sensory dominance,’ which is tested by showing one eye corrected to distance and the other to a myopic target, then compared to the reverse scenario where the fellow eye is corrected to distance and the other to the same myopic target. The combination that feels better is ‘sensory dominance.’ My experience is that motor and sensory dominance correspond 85% of the time,” Dr. Cummings said.

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CATARACT

Dr. Cummings incorporates several tests to determine whether a patient will tolerate monovision, mini monovision, or blended vision and to determine which eye tolerates which tasks. He shows the patient their eyes fully corrected, followed by 0/–1.50 (fully correcting the right eye and correcting the left eye to a myopic target). He asks the patient to rate this out of 100 compared to their prior fully corrected vision. “If this is rated at 80% or higher, the odds of blended vision working are well above 95%,” he said. Then he’ll move to –1.50 in the right eye and fully correct the left. “Score this against the 100% score. If this is scored at 85% or 90%, you have the answer. Correcting the left eye to emmetropia and the right eye for reading is destined to work.” If the score is less than 80%, he puts the patient in a trial frame with the right eye targeted to –1.50 and left eye targeted for emmetropia, giving the patient up to 30 minutes to test this range of vision. “Some will come back saying they love it. Others will say they dislike it, and that rules out blended vision. Others will say that they need more time or that they want to test this in their own home and work environment, and they continue with [a contact lens trial],” Dr. Cummings said. Dr. Cummings tests suppression with the Worth four dot test. Furthermore, he said once the decision is made on the dominant eye, a stereo target is put up on the chart and stereopsis is assessed. Correct both eyes to emmetropia and assess stereopsis. “In my experience, 95% of patients will have good distance stereopsis,” Dr. Cummings said. “Now start defocusing the eye assigned to reading. Ask the patient to continually assess the stereo target and to note when distance stereo is lost. Defocus to –0.25, –0.50, and –0.75. Almost everyone still enjoys stereopsis for distance vision at this level. Once the defocus is –1.00 in the reading eye, some will start losing their stereo vision. For these, their reading target should not exceed –0.75 D. Some can maintain stereo vision up to –1.50 and lose it at –1.75 D. Their reading eye target should not exceed –1.50. A small part of the population can maintain stereo vision at –1.75 and even –2.00 D and have the freedom to select their target.”

Dr. Cummings added that with mono/ blended vision being set with laser vision correction or ICL surgery, there is likely still some residual accommodation, and these patients might receive a slightly less myopic reading target. With a monofocal IOL, he said some may target –1.0 but still require readers, or target –2.0 and then need assistance at intermediate vision. With advanced technology IOLs like EDOF, target emmetropia in the distance eye and –0.75 to –1 in the reading eye for a complete to near complete range of vision, he said. If a patient is seeking a full range of vision but needs to drive at night, Dr. Cummings said dominance again plays a key role in creating a “custom match.” This approach starts with a diffractive trifocal IOL in the non-dominant eye. Prior to the second eye surgery, glare and halo tolerance is assessed. If it’s not bothersome, the patient can choose a trifocal for their dominant eye as well; however, if the patient is bothered with the glare and halo in the non dominant eye, they receive a non-diffractive EDOF IOL in the dominant eye. “With this combination, they have an excellent range of vision and can still drive at night thanks to there being no glare and halos in the dominant eye [with a non-diffractive EDOF],” Dr. Cummings said. Distance and near preferred vision and the LAL Dr. Kopstein, whose sole private practice is performing refractive lens exchange (RLE), said assessing distance and near preferred eyes is important with the Light Adjustable Lens (LAL, RxSight). “It’s an important technology. It’s powerful because it can be adjusted, and it’s equally powerful because of the quality of the optics and the EDOF that you get from the LAL,” Dr. Kopstein said, noting that the original LAL has allowed his practice to get 92% of people completely out of glasses; he thinks this number will rise to 95% with the LAL+. When it comes to distance and near preferred eyes, Dr. Kopstein said his practice has learned that in about 20% of patients, the dominant eye is not their distance preferred eye. “I am one of those people. If you put me in contact lenses that fully correct me for distance and you hold a +1 lens over my right eye and a +1 lens over my left eye, I will

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CATARACT

ASIA-PACIFIC PERSPECTIVES

Myoung Joon Kim, MD Renew Seoul Eye Center 528 Teheran-ro, Gangnam-gu, Seoul, Korea mjmjkim@gmail.com

Shiney Seo, MD RANZCO 501 Stanley Street, South Brisbane,

Queensland, Australia shineyseo@gmail.com

Ocular dominance is not considered much when planning bilateral implantations of the same diffractive trifocal IOLs. However, when mono/blended vision is planned with monofocal or EDOF IOLs, ocular dominance becomes a common starting point of pre-operative planning. Usually, emmetropia is targeted in the dominant eye, while a certain degree of myopia is targeted in the non-dominant eye. It is not unexpected that there is variance in the level of ocular dominance. There are few devices that can quantitatively measure ocular dominance. The concept of patients having different distance/near preferences to their ocular dominance is also intriguing. Diagnostic devices which can evaluate ocular dominance in various aspects will be useful for patient conversations in lens selection. Vision is a complex sensation, with the vision system including two eyes and the brain. The optics of an eye are responsible for forming a sharp image on the retina, with each eye having different optics. Certain optical tolerate the blurring on my right eye more than I will on my non-dominant left eye. About 20% of patients are like this, so it’s important to do dominance testing but also to verify that the dominant eye is indeed the distance preferred eye,” he said. “If you end up adjusting the LAL in the non dominant eye for reading and that’s actually the eye that the patient prefers for distance, you will likely have an unhappy patient.” Dr. Kopstein said the conversation with LAL patients about its EDOF qualities after the light delivery device adjustment calls into question for some patients why you wouldn’t just use monofocal lenses to achieve monovision/blended vision effects.

features can enhance intermediate/near vision. Such optical properties of an eye are changed enormously by a cataract operation. The neural processing of vision which occurs in the brain is not yet well understood, including how it interacts with the optics of the eye. Ocular dominance is the outcome of long-term combination of the eye’s optics and the neural system, which cannot be a simple process. Currently, we are using overly simplified methods such as a finger triangle test to assess ocular dominance. Such methods are seemingly in their infant stages of clinical relevance; a systematic and quantified assessment of ocular dominance could open the doors to numerous research and clinical questions. Depending on the findings, this could potentially become an integral part of the future pre-operative patient assessment and consultation process.

Editors’ note: Dr. Shiney Seo and Dr. Myoung Joon Kim disclosed no relevant financial interests.

“We have been gathering data to answer the question: What are the distance characteristics of the near preferred eye after bilateral LAL lock-in?” he said. “The range of refraction for the near preferred eye with the LAL is plano to –1.75 in our first thousand bilateral ‘lock ins’ (average –0.75). For these near-preferred eyes, the distance vision range is 20/20 to 20/80 (median 20/30). This is very different from ‘standard IOL’ monovision, where the patient closing their distance eye rarely has useful distance vision in the near-preferred eye. This appears to be a unique feature of the LAL compared to the standard monofocal IOL.”

About the Physicians Arthur Cummings, MD | Medical Director, Wellington Eye Clinic, Dublin, Ireland | abc@wellingtoneyeclinic.com Daniel Durrie, MD | Chairman, iOR Partners, Overland Park, Kansas | ddurrie@iorpartners.com Andrew Kopstein, MD | K2 Vision, Seattle, Washington, Scottsdale, Arizona | akopstein@myk2vision.com

Relevant Disclosures Cummings: Alcon Durrie: 2EyeVision Kopstein: None

This article originally appeared in the March 2024 issue of EyeWorld. It has been slightly modified and appears here with permission from the ASCRS Ophthalmic Services Corp.

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EyeWorld Asia Pacific | June 2024

REFRACTIVE SURGERY

Current Accommodating Lenses In Development

by Ellen Stodola, Editorial Co-Director

Creating a true accommodating lens has been a goal for some time in ophthalmology. Several ophthalmologists discussed some of the products currently in development in this space and what makes them unique.

Juvene lens by LensGen This lens comes in two parts, said Sumit “Sam” Garg, MD, with a capsule-filling haptic that has an optic in it and also a receptacle for the action part of the lens, which is a fluid lens. Basically, you put that into the capsular bag, and that maintains the capsular volume, Dr. Garg said. Inside that, in a two-part insertion, you place the fluid lens into the eye and then tab it into place. “There are three tabs, and you pop it into place and that’s what supports the lens inside the eye,” he said. The anterior membrane is deformable, and with accommodative effort, it becomes steeper, which gives you the ability to get this range of vision — distance, intermediate, near. The Juvene lens is a silicone and non-diffractive lens. “Some of the limitations we have with the diffractive optics and presbyopia correction go away because it’s non-diffractive, so you’re not as concerned about other pathologies,” he said. “But on the flip side, you get monofocal-like optics with multifocal-like range, and the conversation becomes easier.” Right now, when people talk about lenses, they usually talk about the great range achieved but rarely marry that with the visual quality performance, Dr. Garg said. “They’ll say, ‘I get great quality,’ but don’t talk about the range. This will allow us to do both at the same time, and because of the proposed mechanism of action, I think that’s really intuitive for patients.”

The Juvene lens. Source: Sumit “Sam” Garg, MD, and LensGen

Dr. Garg said the Juvene lens takes a bit of patient adaptation. “I think it takes a little while for the eye to get used to, at least what we’ve seen in initial trials,” he said. “It’s not necessarily like you put it in and the next day you have full range. Most people see improvement in near and intermediate over the first month or so, but really after 3 months is when it starts to kick in.” The Juvene lens is not currently in an active trial but the company is ramping up for a Phase 1 FDA trial. All the data published so far has been in exploratory study outside of the U.S., Dr. Garg said, so it’s a different patient population but favorable data. He added that data on the lens has been presented at the ASCRS Annual Meeting and has been published in the Journal of Cataract & Refractive Surgery. “We recently presented 3-year data at ASCRS [and] showed maintenance of magnitude of effect, so whatever accommodation you had at year 1, you saw at year 3,” he said, adding that results were the same in respect to contrast sensitivity.

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EyeWorld Asia Pacific | June 2024